This invention relates in general to elastic athletic and orthopedic supports for the human body. More specifically, it relates to an improved support which provides a therapeutic degree of heating only to a strategically placed portion of a body region, and does so without an unacceptable level of perspiration build-up, overheating, or chafing due to fabric rub or bite.
A wide variety of externally applied elastic supports and rigid, joint-immobilizing braces are known to protect healthy and injured joints and to promote healing of certain injuries. Supports and braces are commonly used for injuries and other medical problems at the knee, thighs, elbow, waist, wrist and back. Common injuries that can be helped by a support include strained or torn ligaments, tendinitis, arthritis, and pulled or strained muscles.
Elastic or "soft" supports are usually preferred over braces where the body part is generally healthy and the intent is to support it in order to prevent injury e.g. of a joint and surrounding tissue. Soft supports are also used to protect and promote the healing of injured members where there are no broken bones and the patient is mobile. A support may be worn, for example, before engaging in work or a sports activity that is expected to involve unusual stretching or load bearing. The elasticity of the support is important not only to apply a supporting externally applied compression, but also to maintain the support in a selected position on the body. Ideally the a support in constructed so that in flexes easily and interferes as little as possible with the normal range of motion of the body part. The elasticity of the support also accommodates change in the size of the body part produced by physical exertion, changes in the condition of an injury (e.g., a reduction in swelling), or mere changes in the elevation of the body part, e.g., when an injured ankle is elevated.
The most common form of elas tic support-is a simple tubular sleeve of a stretch fabric such as the stretch nylon material used in Ace.RTM. brand bandages and supports. The sleeve is pulled over and grips the body part to be protected as well as adjoining regions. When used on joints, a major problems are the chafing and bite of the fabric during flexure, particularly at the interior of a joint such as the back of a knee or the "inside" of a elbow. Flexures of body parts and changes in body size can also result in a migration of the position of the support on the body.
To overcome some of those problems, it is also known to construct flat or "unfolding type" supports which wrap around the body part and are secured with straps with hook-and-loop or other fasteners. U.S. Pat. Nos. 4,353,362 to Demarco and U.S. Pat. No. 5,221,252 to the present applicant and another are examples of such supports for knees.
It is also known to combine the support function of these devices with therapeutic heating or cooling functions and protective padding functions. U.S. Pat. No. 5,014,354 to Dumont, for example, uses pads secured to a main elastic body to protect the underlying body portion against falls or other impacts. U.S. Pat. No. 5,168,577 to Detty discloses the use of a continuous layer of neoprene in the material forming the main elastic body where the neoprene acts as an insulator to retain body heat, and thereby increase blood flow to the area. U.S. Pat. No. 5,136,727 to Brisco describes a pair of athletic shorts formed from a pair of conventional ventilated fabric briefs attached to neoprene legs that surround the thighs of the wearer. U.S. Pat. No. 4,964,402 to Grin et al. is illustrative of another approach, the use of pockets formed in the main elastic body where the pockets are adapted to hold hot or cold packets and thereby heat or cool the body region under the pack.
Pockets and thermal packs are not in wide use. They require that packs be heated, cooled or activated, and then supplied to the support for immediate use. These pack heat or cool only for a limited period of time. They must then be removed and replenished or replaced, which typically requires removing the entire support and "reloading" the pockets. The packs are also bulky and they present a significant cost increase as compound to conventional soft supports, and even soft supports with neoprene linings.
A major problem with neoprene and other closed-cell, heat-retaining materials is that they trap perspiration and excessive heat under the support. Trapped moisture and high heat levels quickly produce discomfort and chafing. Moisture also promotes migration because it lubricates the support-skin interface. Such devices cannot be used for extended periods of time, e.g. usually not more than a few hours at the maximum. Another problem is that the neoprene adds to the weight and resistance to flexure of the support as well as promoting chafing and bite. Unless that are enclosed or otherwise protected, neoprene and like products are also susceptible to edge fraying, that is, a ripping and/or crumbling away of the material at its edges.
U.S. Pat. No. 4,832,010 to Lerman discloses a soft support formed from three layer laminate material of neoprene sandwiched between and adhered to two layers of a stretch fabric. The neoprene therefore extends throughout the support. The resilient strength of the neoprene layer is an important source of the supporting compression force. Lerman uses holes that extend only through the neoprene layer to allow an air flow to the body part that removes perspiration and excess heat. Because the holes weaken the neoprene, Lerman teaches that the neoprene must be dense and that the two stretch fabric layers must both be adhered to the neoprene so that their inherent resilience can supplement the compressive force of the neoprene.
Other perforated, closed-cell laminates are known. Cushion sole inserts long for shoes, for example, have a layer of a closed cell foam sandwiched between fabric layers with air holes extending through all three layers.
It is therefore a principal object of this invention to provide an elastic support for a body part, particularly a joint, which also provides a strategically placed therapeutic heating without thermal packs or other external sources of thermal energy.
Another object is to provide the foregoing advantages which also control the build up of moisture at the heated portion of the body part and control chafing and bite, especially during joint flexure.
A further advantage of the present invention is to provide a support with the foregoing advantages which is highly flexible and operate effectively over a range of sizes of the body part.
Still another advantage of the present invention is to provide the foregoing advantages without any significant increase in bulk over a simple elastic sleeve support.
A further object of this invention is to provide all of the foregoing advantages while retaining a favorable cost of manufacture.